TABLE 2

Tissue Distribution at 4, 24, and 48 Hours After Injection

TissueHours after injection
42448
DOTA-NDP-MSHDOTA-MSHoctDOTA-NDP-MSHDOTA-MSHoctDOTA-NDP-MSHDOTA-MSHoct
Blood0.17 ± 0.020.03 ± 0.00*0.03 ± 0.000.00 ± 0.00*0.02 ± 0.000.00 ± 0.00*
Muscle0.94 ± 0.070.03 ± 0.01*0.22 ± 0.020.01 ± 0.00*0.11 ± 0.010.01 ± 0.00*
Liver0.47 ± 0.050.41 ± 0.020.40 ± 0.020.38 ± 0.020.30 ± 0.020.33 ± 0.02
Kidney8.04 ± 0.52 (8.69)13.5 ± 1.12† (21.7)4.93 ± 0.306.56 ± 0.772.38 ± 0.184.89 ± 0.34‡
Spleen0.60 ± 0.050.15 ± 0.01*0.69 ± 0.030.14 ± 0.01*0.61 ± 0.050.14 ± 0.01*
Lung0.23 ± 0.030.10 ± 0.01‡0.19 ± 0.040.04 ± 0.00*0.17 ± 0.010.05 ± 0.00*
Small intestine0.29 ± 0.020.11 ± 0.03†0.33 ± 0.080.06 ± 0.01‡0.35 ± 0.070.04 ± 0.00†
Heart0.06 ± 0.010.03 ± 0.00*0.04 ± 0.000.02 ± 0.00*0.04 ± 0.010.02 ± 0.00
Bone1.29 ± 0.060.08 ± 0.01*1.07 ± 0.070.07 ± 0.00*0.83 ± 0.040.08 ± 0.01*
Pancreas0.15 ± 0.010.03 ± 0.00*0.12 ± 0.010.02 ± 0.00*0.12 ± 0.010.02 ± 0.00‡
Skin0.94 ± 0.100.10 ± 0.02*0.56 ± 0.050.06 ± 0.01*0.44 ± 0.040.08 ± 0.01*
Stomach0.41 ± 0.070.10 ± 0.02‡0.38 ± 0.120.25 ± 0.040.15 ± 0.020.11 ± 0.01
AdrenalND0.18 ± 0.04ND0.13 ± 0.01ND0.31 ± 0.10
Tumor6.32 ± 0.16 (1.15)4.31 ± 0.30† (0.45)2.74 ± 0.001.17 ± 0.13*1.20 ± 0.111.08 ± 0.18

  • ↵* P < 0.0001 vs 111ln-DOTA-NDP-MSH.

  • ↵† P < 0.01 vs 111ln-DOTA-NDP-MSH.

  • ↵‡ P < 0.001 vs 111ln-DOTA-NDP-MSH.

  • ND = not determined.

  • 111ln-DOTA-MSHoct or 111ln-DOTA-NDP-MSH was injected to melanoma-bearing mice, and tissue-associated radioactivity was measured 4, 24, and 48 h after injection. Results are expressed as %ID/g (mean ± SEM, n = 4–8). Value in parentheses indicates tissue uptake in presence of 50 μg α-MSH. Tumor uptake 4, 24, and 48 h after injection was independent of tumor size as indicated by absence of statistically significant linear relationship between tumor size and tumor uptake (slope of linear correlation curve = −0.104 and 0.028; R2 = 0.08 and 0.09; P = 0.24 and 0.30 for 111In-DOTA-MSHoct and 111In-DOTA-NDP-MSH, respectively).